GIANT BLAST: John Buck congratulates Marlon Byrd after Byrd’s two-run homer in yesterday’s 7-2 win over the Giants to complete a series sweep in San Francisco. Byrd hit homers in each of his past two games.

SAN FRANCISCO — Perhaps John Buck’s success at the plate during the Mets road trip is a harbinger of good things to come in the second half of the season for the previously slumping catcher.

The Mets certainly hope so.

Buck, who has struggled at the plate with his average this season (.213 after yesterday’s game), has caught fire in July, as demonstrated during the Mets recent series at Milwaukee and three-game sweep of the free-falling Giants, sealed with a 7-2 win yesterday.

Buck is 6 for 18 in his past four games and has 10 RBIs in his past nine, including at least one in four straight games.

“The good thing is I didn’t realize [about the RBI streak],” Buck said jokingly. “I felt good, even last month. It was the baseball gods saying, ‘Stay the course because you are hitting the ball.’ Now I am getting some results which helps you kind of relax. ”

Buck had two RBIs yesterday on a first-inning single, which gave the Mets a 3-0 lead and chased Giants starter Matt Cain after just seven batters. Buck had been 0 for 10 against Cain in his career.

“It was a cutter down and away,” Buck said. “It’s always good driving in runs, especially off a pitcher like that.”

Buck also smashed a double to deep center field to lead off the sixth and came around to score on pitcher Zack Wheeler’s double for a 6-0 lead. Buck flew out in the fourth and seventh innings for a 2-for-4 day.

“I’m obviously swinging at better pitches,” he said.

Despite the low batting average, Buck has good power numbers (14 home runs, 46 RBIs) and is second on the team in round-trippers and RBIs to Marlon Byrd (15 HR, 49 RBIs), who homered in each of his past two games.

Lately “Buck has been swinging the bat really well and not getting some of the results that I think he deserved. He is squaring more balls up for sure and hitting more line-drives,” said backup catcher Anthony Recker, who hit a home run against Barry Zito in Tuesday’s Mets win. “Today Buck got some of those results, and I have been fortunate enough to contribute a little bit, too.

“Obviously, anytime we [catchers] can do that, that is going to help the team out a lot offensively and take pressure off some of the other guys.”

The issue for the Mets is Buck hit nine of his 14 homers in April, tying him for the most ever by a Mets player with Carlos Delgado (2006) and Dave Kingman (1976). Since May 5, however, Buck has had a big-time power outage with just five home runs.

Buck, a nine-year veteran and in his first year with the Mets, started off the trip with a bang, hitting a home run in Milwaukee on July 6 as the centerpiece of his renaissance.

“It is good to see Buck swinging the bat well again,” reliever LaTroy Hawkins said. “I’m sure he is putting a lot of work in the cage to stay away from how he was feeling I guess the last month and a half.”